How to Care for Houseplants in the Winter

I have four beautiful houseplants that I kept outside all summer. Now that I have brought them in for the Winter the leaves are turning yellow and falling off. What do I need to do?

Hi Diane,

When you bring houseplants indoors for the winter, the way you care for them changes dramatically. LESS is the word to remember: there is less light and less humidity than when the plants were outside, so they need less water and less plant food.

Light: During the winter, the sun is lower in the sky and light coming through the windows can be up to 50% less than light during the spring and summer months coming through the same windows. Plants that you’ve brought in from the outside or had near a northern or eastern facing window may have to be moved to a southern or western facing window. You should also move plants close to your windows. Keep your plant leaves dust free so they can absorb as much light as possible, and add fluorescent bulbs to provide an additional light source if necessary.

Water: Over-watering is the main reason houseplants die during the winter. Most houseplants need to dry out quite a bit before being watered during the winter months. Check for moisture not only on the surface of the plant, but also find out how wet the soil is near the roots. One way to do this by lifting the plant right after you’ve watered and feeling how heavy it is. When the soil is dry, the pot will be much lighter when you lift it. I prefer to get my fingers dirty by sticking them into the soil as far as possible, at least 3.” Sometimes I use a long pencil to carefully dig a hole deep into the soil, being careful to avoid damaging the roots. If it comes out with wet soil stuck to it, I know the plant doesn’t need water. It’s like using a tooth pick to test if a cake is done. Ferns are the exception, these plants need to stay moist even in winter.

fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small.: Houseplants need plant food only when they are actively growing. During the winter, when plants are resting, don’t fertilize them. If you feed plants that aren’t producing new growth, the fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small. is not absorbed, the salts in the food build up in the soil and burns the leaves.

Humidity: Due to the heat we all use in our homes and offices during the winter, relative humidity is reduced to only 10-15%.  Houseplants prefer 40-50% relative humidity.  When the humidity is too low, plants develop brown leaf tips and often get a plant pest called spider mitesSpider Mites, members of the Acari family, are small insects about 1mm in size. The most common indoor plant mite is the red spider mite (also called the two-spotted spider mite.). These pests lay their eggs on the under surface of leaves and produce fine webbing especially where the leaves are attached to the stem. Spider mites are hard to see with the naked eye, and may appear only as small red dots. They are more often recognized by the gritty feel of the leaf when you run your finger down it’s length, or by the appearance of discolored leaves due to the sucking action of the mites. The best way to prevent spider mites is to keep your plants clean and dust free. Treat spider mites by spraying every ten days for a month with a product such as Safer Insecticidal Soap.. There are several ways to increase humidity. Group plants together to create a mini green house effect. Place a small humidifier in the room. Set your plant on a wet pebble tray. A wet pebble tray is simply a shallow dish lined with small rocks or pebbles. Keep the water just below the small rocks so that the plant never sits in the water. As the water evaporates it increases the humidity in the air. Refill the water as needed.

Pruning: Take the time to pinch back stem tips, you’ll be rewarded with lots of new growth and a bushy plant in the spring.